Mitochondrial DNA Levels Research Articles

Screening mitochondria-related biomarkers in skin and plasma of atopic dermatitis patients by bioinformatics analysis and machine learning.

There is a significant imbalance of mitochondrial activity and oxidative stress (OS) status in patients with atopic dermatitis (AD). This study aims to screen skin and peripheral mitochondria-related biomarkers, providing insights into the underlying mechanisms of mitochondrial dysfunction in AD. Public data were obtained from MitoCarta 3.0 and GEO database. We screened mitochondria-related differentially expressed genes (MitoDEGs) using R language and then performed GO and KEGG pathway analysis on MitoDEGs. PPI and machine learning algorithms were also used to select hub MitoDEGs. Meanwhile, the expression of hub MitoDEGs in clinical samples were verified. Using ROC curve analysis, the diagnostic performance of risk model constructed from these hub MitoDEGs was evaluated in the training and validation sets. Further computer-aided algorithm analyses included gene set enrichment analysis (GSEA), immune infiltration and mitochondrial metabolism, centered on these hub MitoDEGs. We also used real-time PCR and Spearman method to evaluate the relationship between plasma circulating cell-free mitochondrial DNA (ccf-mtDNA) levels and disease severity in AD patients. MitoDEGs in AD were significantly enriched in pathways involved in mitochondrial respiration, mitochondrial metabolism, and mitochondrial membrane transport. Four hub genes (BAX, IDH3A, MRPS6, and GPT2) were selected to take part in the creation of a novel mitochondrial-based risk model for AD prediction. The risk score demonstrated excellent diagnostic performance in both the training cohort (AUC = 1.000) and the validation cohort (AUC = 0.810). Four hub MitoDEGs were also clearly associated with the innate immune cells' infiltration and the molecular modifications of mitochondrial hypermetabolism in AD. We further discovered that AD patients had considerably greater plasma ccf-mtDNA levels than controls (U = 92.0, p< 0.001). Besides, there was a significant relationship between the up-regulation of plasma mtDNA and the severity of AD symptoms. The study highlights BAX, IDH3A, MRPS6 and GPT2 as crucial MitoDEGs and demonstrates their efficiency in identifying AD. Moderate to severe AD is associated with increased markers of mitochondrial damage and cellular stress (ccf=mtDNA). Our study provides data support for the variation in mitochondria-related functional characteristics of AD patients.

Role of mitochondrial DNA level in epidural-related maternal fever: a single-centre, observational, pilot study

IntroductionEpidural analgesia has been associated with intrapartum maternal fever development. Epidural-related maternal fever (ERMF) is believed to be based on a non-infectious inflammatory reaction. Circulating cell-free mitochondrial deoxyribonucleic acid (mtDNA) is one of the possible triggers of sterile inflammatory processes; however, a connection has not been investigated so far. Therefore, this study aimed to investigate cell-free mtDNA alterations in women in labour with ERMF in comparison with non-febrile women.Material and methodsA total of 60 women in labour were assessed for maternal temperature every 4 h and blood samples were obtained at the beginning and after delivery. Depending on the analgesia and the development of fever (axillary temperature ≥ 37.5 °C), the women were allocated either to the group of no epidural analgesia (n = 17), to epidural analgesia no fever (n = 34) or to ERMF (n = 9). Circulating cell-free mtDNA was analysed in the maternal plasma for the primary outcome whereas secondary outcomes include the evaluation of inflammatory cytokine release, as well as placental inflammatory signs.ResultsOf the women with epidural analgesia, 20% (n = 9) developed ERMF and demonstrated a decrease of circulating mtDNA levels during labour (p = 0.04), but a trend towards higher free nuclear DNA. Furthermore, women with maternal pyrexia showed a 1.5 fold increased level of Interleukin-6 during labour. A correlation was found between premature rupture of membranes and ERMF.ConclusionsThe pilot trial revealed an evident obstetric anaesthesia phenomenon of maternal fever due to epidural analgesia in 20% of women in labour, demonstrating counterregulated free mtDNA and nDNA. Further work is urgently required to understand the connections between the ERMF occurrence and circulating cell-free mtDNA as a potential source of sterile inflammation.Trial registrationNCT0405223 on clinicaltrials.gov (registered on 25/07/2019).

CGAS/STING signaling pathway-mediated microglial activation in the PFC underlies chronic ethanol exposure-induced anxiety-like behaviors in mice

Chronic ethanol consumption is a prevalent condition in contemporary society and exacerbates anxiety symptoms in healthy individuals. The activation of microglia, leading to neuroinflammatory responses, may serve as a significant precipitating factor; however, the precise molecular mechanisms underlying this phenomenon remain elusive. In this study, we initially confirmed that chronic ethanol exposure (CEE) induces anxiety-like behaviors in mice through open field test and elevated plus maze test. The cGAS/STING signaling pathway has been confirmed to exhibits a significant association with inflammatory signaling responses in both peripheral and central systems. Western blot analysis confirmed alterations in the cGAS/STING signaling pathway during CEE, including the upregulation of p-TBK1 and p-IRF3 proteins. Moreover, we observed microglial activation in the prefrontal cortex (PFC) of CEE mice, characterized by significant alterations in branching morphology and an increase in cell body size. Additionally, we observed that administration of CEE resulted in mitochondrial dysfunction within the PFC of mice, accompanied by a significant elevation in cytosolic mitochondrial DNA (mtDNA) levels. Furthermore, our findings revealed that the inhibition of STING by H-151 effectively alleviated anxiety-like behavior and suppressed microglial activation induced by CEE. Our study unveiled a significant association between anxiety-like behavior, microglial activation, inflammation, and mitochondria dysfunction during CEE.

Imeglimin modulates mitochondria biology and facilitates mitokine secretion in 3T3-L1 adipocytes

AimsImeglimin, a novel antidiabetic drug, has recently been reported to affect pancreatic β-cells and hepatocytes. Adipose tissue plays a crucial role in systemic metabolism. However, its effect on adipocytes remains unexplored. Herein, we investigated the effects of imeglimin on adipocytes, particularly in the mitochondria. Main methodsThe 3T3-L1 adipocytes were treated with imeglimin. Mitochondrial respiratory complex I activity and NAD+, NADH, and AMP levels were measured. Protein expression levels were determined by western blotting, mitochondrial DNA and mRNA expression levels were determined using quantitative polymerase chain reaction, and secreted adipocytokine and mitokine levels were determined using adipokine array and enzyme-linked immunosorbent assay. Key findingsImeglimin inhibited complex I activity, decreased the NAD+/NADH ratio, and increased AMP levels, which were associated with the enhanced phosphorylation of AMP-activated protein kinase. In addition, imeglimin increased the mitochondrial DNA content and levels of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-γ coactivator 1-α mRNA, which were abolished by Ly294002, a phosphoinositide 3-kinase inhibitor. Furthermore, imeglimin facilitated the expression levels of markers of the mitochondrial unfolded protein response, and the gene expression and secretion of two mitokines, fibroblast growth factor 21 and growth differentiation factor 15. The production of both mitokines was transcriptionally regulated and abolished by phosphoinositide 3-kinase and Akt inhibitors. SignificanceImeglimin modulates mitochondrial biology in adipocytes and may exert a mitohormetic effect through mitokine secretion.

Dapagliflozin Alleviates Myocardial Ischaemia Reperfusion Injury by Activating Mitophagy via the AMPK-PINK1/Parkin Signalling Pathway.

Myocardial ischaemia reperfusion injury (MIRI) determines infarct size and long-term outcomes after acute myocardial infarction (AMI). Dapagliflozin, a sodium-glucose cotransporter 2 inhibitor, alleviates MIRI in animal models. We investigated the potential mechanisms underlying the cardioprotective effect of dapagliflozin against MIRI, focusing on mitochondrial injury and mitophagy. MIRI mouse and H9C2 cell models were established. 2,3,5-Triphenyltetrazolium chloride (TTC) staining showed a significant alleviation of MIRI after pre-treatment of dapagliflozin compared to the model group (14.91 ± 1.76 vs. 40.47 ± 3.69%). Data from the pre-treatment dapagliflozin group showed a significant decrease in left ventricular ejection fraction (LVEF) (44.8 ± 2.7 vs. 28.5 ± 5.3%, P<0.01), left ventricular end-diastolic volume (LVEDV) (70.6 ± 9.5 vs. 93.5 ± 13.8 ul, P<0.05), and left ventricular end-systolic volume (LVESV) (39.0 ± 8.3 vs. 67.9 ± 13.7 ul, P<0.05) compared to the model group. Dapagliflozin also reduced the levels of reactive oxygen species (ROS) and fragmented mitochondrial DNA, reversed the decrease in mitochondrial membrane potential, and suppressed apoptosis. Further study showed that dapagliflozin could protect against mitochondrial injury by rapidly clearing damaged mitochondria via mitophagy in a phosphatase and tensin homologue (PTEN)-induced putative kinase 1 (PINK1)/parkindependent manner. Dapagliflozin regulated mitophagy in cardiomyocytes by suppressing the adenosine 5'monophosphate-activated protein kinase (AMPK)-PINK1/parkin signalling pathway, resulting in attenuated MIRI. Dapagliflozin alleviated MIRI by activating mitophagy via the AMPK-PINK1/parkin signalling pathway.

PARKIN is not required to sustain OXPHOS function in adult mammalian tissues

Loss-of-function variants in the PRKN gene encoding the ubiquitin E3 ligase PARKIN cause autosomal recessive early-onset Parkinson’s disease (PD). Extensive in vitro and in vivo studies have reported that PARKIN is involved in multiple pathways of mitochondrial quality control, including mitochondrial degradation and biogenesis. However, these findings are surrounded by substantial controversy due to conflicting experimental data. In addition, the existing PARKIN-deficient mouse models have failed to faithfully recapitulate PD phenotypes. Therefore, we have investigated the mitochondrial role of PARKIN during ageing and in response to stress by employing a series of conditional Parkin knockout mice. We report that PARKIN loss does not affect oxidative phosphorylation (OXPHOS) capacity and mitochondrial DNA (mtDNA) levels in the brain, heart, and skeletal muscle of aged mice. We also demonstrate that PARKIN deficiency does not exacerbate the brain defects and the pro-inflammatory phenotype observed in mice carrying high levels of mtDNA mutations. To rule out compensatory mechanisms activated during embryonic development of Parkin-deficient mice, we generated a mouse model where loss of PARKIN was induced in adult dopaminergic (DA) neurons. Surprisingly, also these mice did not show motor impairment or neurodegeneration, and no major transcriptional changes were found in isolated midbrain DA neurons. Finally, we report a patient with compound heterozygous PRKN pathogenic variants that lacks PARKIN and has developed PD. The PARKIN deficiency did not impair OXPHOS activities or induce mitochondrial pathology in skeletal muscle from the patient. Altogether, our results argue that PARKIN is dispensable for OXPHOS function in adult mammalian tissues.

The Schizosaccharomyces pombe DEAD-box protein Mss116 is required for mitoribosome assembly and mitochondrial translation

DEAD-box helicases are important players in mitochondrial gene expression, which is necessary for mitochondrial respiration. In this study, we characterized Schizosaccharomyces pombe Mss116 (spMss116), a member of the family of DEAD-box RNA helicases. Deletion of spmss116 in a mitochondrial intron-containing background significantly reduced the levels of mitochondrial DNA (mtDNA)-encoded cox1 and cob1 mRNAs and impaired mitochondrial translation, leading to a severe respiratory defect and a loss of cell viability during stationary phase. Deletion of mitochondrial introns restored the levels of cox1 and cob1 mRNAs to wide-type (WT) levels but could not restore mitochondrial translation and respiration in Δspmss116 cells. Furthermore, deletion of spmss116 in both mitochondrial intron-containing and intronless backgrounds impaired mitoribosome assembly and destabilization of mitoribosomal proteins. Our findings suggest that defective mitochondrial translation caused by deletion of spmss116 is most likely due to impaired mitoribosome assembly.

Visualized Tracking and Multidimensional Assessing of Mitochondria-Associated Pyroptosis in Cancer Cells by a Small-Molecule Fluorescent Probe.

Pyroptosis is closely related to the development and treatment of various cancers; thus, comprehensive studies of the correlations between pyroptosis and its inductive or inhibitive factors can provide new ideas for the intervention and diagnosis of tumors. The dysfunction of mitochondria may induce pyroptosis in cancer cells, which can be reflected by the fluctuations of the microenvironmental parameters in mitochondria as well as the changes of mitochondrial DNA level and morphology, etc. To precisely track and assess the mitochondria-associated pyroptosis process, simultaneous visualization of changes in multiphysiological parameters in mitochondria is highly desirable. In this work, we reported a nonreaction-based, multifunctional small-molecule fluorescent probe Mito-DK with the capability of crosstalk-free response to polarity and mtDNA as well as mitochondrial morphology. Accurate assessment of mitochondria-associated pyroptosis induced by palmitic acid/H2O2 was achieved through monitoring changes in mitochondrial multiple parameters with the help of Mito-DK. In particular, the pyroptosis-inducing ability of an antibiotic doxorubicin and the pyroptosis-inhibiting capacity of an anticancer agent puerarin were evaluated by Mito-DK. These results provide new perspectives for visualizing mitochondria-associated pyroptosis and offer new approaches for screening pyroptosis-related anticancer agents.

Rapamycin alleviates mitochondrial dysfunction in anti-NMDAR encephalitis mice

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most prevalent forms of autoimmune encephalitis, characterized by a series of neurological and psychiatric symptoms, including cognitive impairment, seizures and psychosis. The underlying mechanism of anti-NMDAR encephalitis remains unclear. In the current study, the mouse model of anti-NMDAR encephalitis with active immunization was performed. We first uncovered excessive mitochondrial fission in the hippocampus and temporal cortex of anti-NMDAR encephalitis mice, indicated by elevated level of Phospho-DRP1 (Ser616) (p-Drp1-S616). Moreover, blockade of the autophagic flux was also demonstrated, leading to the accumulation of fragmented mitochondria, and elevated levels of mitochondrial reactive oxygen species (mtROS) and mitochondrial DNA (mtDNA) in anti-NMDAR encephalitis. More importantly, we found that the mTOR signaling pathway was overactivated, which could aggravate mitochondrial fission and inhibit autophagy, resulting in mitochondrial dysfunction. While rapamycin, the specific inhibitor of the mTOR signaling pathway, significantly alleviated mitochondrial dysfunction by inhibiting mitochondrial fission and enhancing autophagy. Levels of mtROS and mtDNA were markedly reduced after the treatment of rapamycin. In addition, rapamycin also significantly alleviated cognitive dysfunction and anxious behaviors found in anti-NMDAR encephalitis mice. Thus, our study reveals the vital role of mitochondrial dysfunction in pathological mechanism of anti-NMDAR encephalitis and lays a theoretical foundation for rapamycin to become a clinically targeted drug for anti-NMDAR encephalitis.

GSDMD induces hepatocyte pyroptosis to trigger alcoholic hepatitis through modulating mitochondrial dysfunction

BackgroundMechanisms and consequences of Gasdermin D (GSDMD) activation in alcoholic hepatitis (AH) are unclear. In the present study, we investigated whether GSDMD induces hepatocyte pyroptosis by regulating mitochondrial dysfunction in AH.ResultsLiver damage in AH mice was assessed by HE staining, serum levels of AST, ALT, TC, and TG. The levels of IL-1β, IL-18, LDH, inflammasome-associated proteins and hepatocyte death were assessed to determine pyroptosis. Mitochondrial dysfunction was assessed through various parameters including mitochondrial DNA (mtDNA) levels, ROS generation, mitochondrial membrane potential, ATP contents, levels of mitochondrial function-related proteins and morphological changes of mitochondria. AH induced gasdermin D (GSDMD) activation, leading to increased protein expression of N-terminal GSDMD (GSDMD-N), NLRP3, and Caspase 11 in liver tissues. Downregulation of GSDMD alleviated alcohol-induced hepatocyte pyroptosis. Alcohol also causes mitochondrial dysfunction in hepatocytes in AH, which was improved by inhibiting GSDMD. Furthermore, enhancing mitochondrial function suppressed alcohol-induced hepatocyte pyroptosis. Further, knockdown of GSDMD or dynamin-related protein 1 (Drp1) improved AH-induced liver injury, accompanied by a decrease in hepatocyte pyroptosis.ConclusionGSDMD induces hepatocyte pyroptosis by modulating mitochondrial dysfunction during AH-induced inflammation and liver injury. These findings may pave the way to develop new therapeutic treatments for AH.

Increased circulating cell-free mitochondrial DNA in plasma of first-diagnosed drug-naïve bipolar disorder patients: A case-control and 4-week follow-up study

BackgroundThe study of clinical biological indicators in bipolar disorder (BD) is important. In recent years, basic experiments have associated the pathophysiological mechanism of BD is related to mitochondrial dysfunction, but few clinical studies have confirmed this finding. ObjectThe present study aimed to evaluate whether plasma circulating cell-free mitochondrial DNA (ccf-mtDNA) levels, which can represent the degree of mitochondrial damage in vivo, are altered in patients with BD in early onset and during treatment compared with controls. MethodA total of 75 first-diagnosed drug-naive patients with BD and 60 HCs were recruited and followed up for 1 month. The clinical symptoms were assessed using HAMD, HAMA, and YMRS, and ccf-mtDNA levels were measured by qPCR before and after drug treatment in BD. Result(1) The plasma ccf-mtDNA levels in first-diagnosed drug-naive patients with BD increased compared with those in HCs (p = 0.001). (2) Drug treatment for 1 month can decrease the expression of ccf-mtDNA in BD (p < 0.001). (3) No significant correlation was observed between the changes in ccf-mtDNA levels and the improvement of clinical symptoms in BD after drug treatment. ConclusionThe plasma ccf-mtDNA level was increased in BD, and decreased after pharmacological treatment. These outcomes suggested that plasma ccf-mtDNA level is likely to be sensitive to the drug response in BD, and mitochondrial pathway is a potential target for further therapy.

Inhibition of mtDNA-PRRs pathway-mediated sterile inflammation by astragalus polysaccharide protects against transport stress-induced cardiac injury in chicks

Transport stress (TS) not only weakens poultry performance but also affects animal welfare. Additionally, TS can evoke cardiac damage by triggering sterile inflammation in chicks, but the underlying mechanism is not fully understood. Here, we aimed to elucidate how TS induces sterile inflammation and heart injury and to clarify the antagonism effect of astragalus polysaccharides (APS). We randomly divided 60 chicks (one-day-old female) into 5 groups (n = 12): Control_0h (Con_0h) group (chicks were slaughtered at initiation), Control group (stress-free control), TS group (simulated TS exposure for 8 h), TS plus water (TS+W) group, and TS plus APS (TS+APS) group. Before simulation transport, the chicks of TS+W and TS+APS groups were, respectively, dietary with 100 μL of water or APS (250 μg/mL). H&E staining was employed for cardiac histopathological observation. ELISA assay was used to measure oxidative stress marker levels (GSH, GPX, GST, and MDA). A commercial kit was used to isolate the mitochondrial portion, and qRT-PCR was employed to measure the mitochondrial DNA (mtDNA) levels. Furthermore, we evaluated the activity of mtDNA-mediated NF-κB, NLRP3 inflammasome, and cGAS-STING inflammatory pathways and the expression of downstream inflammatory factors by Western Blotting or qRT-PCR. Our findings revealed that APS notably relieved TS-induced myocardial histopathological lesions and infiltrations. Likewise, the decrease in proinflammatory factors (TNF-α, IL-1β, and IL-6) and IFN-β by APS further supported this result. Meanwhile, TS caused severe oxidative stress in the chick heart, as evidenced by decreased antioxidant enzymes and increased MDA. Importantly, APS prevented mtDNA stress and leakage by reducing oxidative stress. Interestingly, TS-induced mtDNA leakage caused a series of inflammation events via mtDNA-PRRs pathways, including TLR21-NF-κB, NLRP3 inflammasome, and cGAS-STING signaling. Encouragingly, all these adverse changes related to inflammation events induced by mtDNA-PRRs activation were all relieved by APS treatment. In summary, our findings provide the first evidence that inhibition of mtDNA-PRRs pathway-mediated sterile inflammation by APS could protect against TS-induced cardiac damage in chicks.

Yinhuang granule alleviates carbon tetrachloride-induced liver fibrosis in mice and its mechanism.

Liver fibrosis is a formidable global medical challenge, with no effective clinical treatment currently available. Yinhuang granule (YHG) is a proprietary Chinese medicine comprising Scutellariae Radix and Lonicerae Japonicae Flos. It is frequently used for upper respiratory tract infections, pharyngitis, as well as acute and chronic tonsillitis. To investigate the potential of YHG in alleviating carbon tetrachloride (CCl4)-induced liver fibrosis in mice. To induce a hepatic fibrosis model in mice, this study involved intraperitoneal injections of 2 mL/kg of CCl4 twice a week for 4 wk. Meanwhile, liver fibrosis mice in the low dose of YHG (0.4 g/kg) and high dose of YHG (0.8 g/kg) groups were orally administered YHG once a day for 4 wk. Serum alanine/aspartate aminotransferase (ALT/AST) activity and liver hydroxyproline content were detected. Sirius red and Masson's trichrome staining assay were conducted. Real-time polymerase chain reaction, western-blot and enzyme-linked immunosorbent assay were conducted. Liver glutathione content, superoxide dismutase activity level, reactive oxygen species and protein carbonylation amount were detected. The administration of YHG ameliorated hepatocellular injury in CCl4-treated mice, as reflected by decreased serum ALT/AST activity and improved liver histological evaluation. YHG also attenuated liver fibrosis, evident through reduced liver hydroxyproline content, improvements in Sirius red and Masson's trichrome staining, and lowered serum hyaluronic acid levels. Furthermore, YHG hindered the activation of hepatic stellate cells (HSCs) and ameliorated oxidative stress injury and inflammation in liver from CCl4-treated mice. YHG prompted the nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and upregulated the expression of Nrf2-dependent downstream antioxidant genes. In addition, YHG promoted mitochondrial biogenesis in liver from CCl4-treated mice, as demonstrated by increased liver adenosine triphosphate content, mitochondrial DNA levels, and the expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha and nuclear respiratory factor 1. YHG effectively attenuates CCl4-induced liver fibrosis in mice by inhibiting the activation of HSCs, reducing inflammation, alleviating liver oxidative stress damage through Nrf2 activation, and promoting liver mitochondrial biogenesis.

Mitochondrial DNA levels in perfusate and bile during ex vivo normothermic machine correspond with donor liver quality

Ex vivo normothermic machine perfusion (NMP) preserves donor organs and permits real-time assessment of allograft health, but the most effective indicators of graft viability are uncertain. Mitochondrial DNA (mtDNA), released consequent to traumatic cell injury and death, including the ischemia-reperfusion injury inherent in transplantation, may meet the need for a biomarker in this context. We describe a real time PCR-based approach to assess cell-free mtDNA during NMP as a universal biomarker of allograft quality. Measured in the perfusate fluid of 29 livers, the quantity of mtDNA correlated with metrics of donor liver health including International Normalized Ratio (INR), lactate, and warm ischemia time, and inversely correlated with inferior vena cava (IVC) flow during perfusion. Our findings endorse mtDNA as a simple and rapidly measured feature that can inform donor liver health, opening the possibility to better assess livers acquired from extended criteria donors to improve organ supply.

A tight interplay between platelet activation and mitochondrial DNA release promotes platelet storage lesion in platelet concentrates.

Platelet storage lesion (PSL) adversely affects the quality of platelet concentrates (PCs). Platelets are prone to activation during storage. Moreover, elevated free mitochondrial DNA (mtDNA) levels in PCs are associated with a higher risk of adverse transfusion reactions. Therefore, we aimed to evaluate the correlation between platelet activation markers and mtDNA release during PC storage. Six PCs prepared by the platelet-rich plasma method were assessed for free mtDNA copy number using quantitative real-time PCR and CD62P (P-selectin) expression by flow cytometry on days 0 (PC collection day), 3, 5 and 7 of storage. Lactate dehydrogenase (LDH) activity, pH, platelet count, mean platelet volume (MPV) and platelet distribution width (PDW) were measured as well. The correlation between free mtDNA and other PSL parameters, and the correlation between all parameters, was determined. Significant increases in free mtDNA, MPV and PDW, and a significant decrease in platelet count and pH were observed. CD62P expression and LDH activity elevated significantly, particularly on storage days 5-7 and 0-3, respectively. Moreover, a moderate positive correlation (r = 0.61) was observed between free mtDNA and CD62P expression. The r values between free mtDNA and LDH, pH, platelet count, MPV and PDW were 0.81, -0.72, -0.49, 0.81 and 0.77, respectively. The interplay between platelet activation and mtDNA release in promoting PSL in PCs may serve as a promising target for future research on applying additive solutions and evaluating the quality of PCs to improve transfusion and clinical outcomes.

Mitochondrial DNA structuring of Antarctic prions (Pachyptila desolata, Procellariidae)

Prions (Pachyptila) are small seabirds with a Southern Hemisphere breeding distribution. Antarctic prion (Pachyptila desolata) and Salvin’s prion (P. salvini) are two species that are regularly recorded in New Zealand as beach-wrecks but they are difficult to distinguish morphologically. Salvin’s prion is restricted to breeding on the Prince Edward Islands and Crozet Islands in the Indian Ocean but Antarctic prions have a circumpolar breeding distribution on numerous sub-Antarctic and Antarctic islands in the Southern, South Atlantic and Indian Oceans. Our aim was to examine the level of mitochondrial DNA (mtDNA) structuring within Antarctic prion and Salvin’s prion colonies, to test whether this technique can determine the provenance of beach-cast birds. The Auckland Islands Antarctic prion population exhibited distinct mtDNA haplotypes from all other populations, supporting the suggestion that these islands may have been an ice-free refugium during the Last Glacial Maximum. All other sampled breeding populations shared haplotypes, limiting the use of these sequences for determining the provenance of beach-cast birds. None of our museum specimens of Salvin’s prion collected from breeding colonies produced DNA sequences. This result indicates that the method by which these specimens, which were collected in the 1960s and 70s, were preserved, or subsequent treatments, has resulted in the loss of their DNA.

Cell-free DNA levels associate with COPD exacerbations and mortality

The question addressed by the studyGood biological indicators capable of predicting chronic obstructive pulmonary disease (COPD) phenotypes and clinical trajectories are lacking. Because nuclear and mitochondrial genomes are damaged and released by cigarette smoke exposure, plasma cell-free mitochondrial and nuclear DNA (cf-mtDNA and cf-nDNA) levels could potentially integrate disease physiology and clinical phenotypes in COPD. This study aimed to determine whether plasma cf-mtDNA and cf-nDNA levels are associated with COPD disease severity, exacerbations, and mortality risk.Materials and methodsWe quantified mtDNA and nDNA copy numbers in plasma from participants enrolled in the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE, n = 2,702) study and determined associations with relevant clinical parameters.ResultsOf the 2,128 participants with COPD, 65% were male and the median age was 64 (interquartile range, 59–69) years. During the baseline visit, cf-mtDNA levels positively correlated with future exacerbation rates in subjects with mild/moderate and severe disease (Global Initiative for Obstructive Lung Disease [GOLD] I/II and III, respectively) or with high eosinophil count (≥ 300). cf-nDNA positively associated with an increased mortality risk (hazard ratio, 1.33 [95% confidence interval, 1.01–1.74] per each natural log of cf-nDNA copy number). Additional analysis revealed that individuals with low cf-mtDNA and high cf-nDNA abundance further increased the mortality risk (hazard ratio, 1.62 [95% confidence interval, 1.16–2.25] per each natural log of cf-nDNA copy number).Answer to the questionPlasma cf-mtDNA and cf-nDNA, when integrated into quantitative clinical measurements, may aid in improving COPD severity and progression assessment.

Effects of Particulate Matter Inhalation during Exercise on Oxidative Stress and Mitochondrial Function in Mouse Skeletal Muscle.

Particulate matter (PM) has deleterious consequences not only on the respiratory system but also on essential human organs, such as the heart, blood vessels, kidneys, and liver. However, the effects of PM inhalation on skeletal muscles have yet to be sufficiently elucidated. Female C57BL/6 or mt-Keima transgenic mice were randomly assigned to one of the following four groups: control (CON), PM exposure alone (PM), treadmill exercise (EX), or PM exposure and exercise (PME). Mice in the three-treatment group were subjected to treadmill running (20 m/min, 90 min/day for 1 week) and/or exposure to PM (100 μg/m3). The PM was found to exacerbate oxidative stress and inflammation, both at rest and during exercise, as assessed by the levels of proinflammatory cytokines, manganese-superoxide dismutase activity, and the glutathione/oxidized glutathione ratio. Furthermore, we detected significant increases in the levels of in vivo mitophagy, particularly in the PM group. Compared with the EX group, a significant reduction in the level of mitochondrial DNA was recorded in the PME group. Moreover, PM resulted in a reduction in cytochrome c oxidase activity and an increase in hydrogen peroxide generation. However, exposure to PM had no significant effect on mitochondrial respiration. Collectively, our findings in this study indicate that PM has adverse effects concerning both oxidative stress and inflammatory responses in skeletal muscle and mitochondria, both at rest and during exercise.

Oxidative Stress: A Biomarker for Animal Health and Production: A Review

Oxidative stress occurs when there is an imbalance between free radicals and antioxidants in body. Body produces free radicals during metabolic processes which are neutralized by antioxidants. However, too many free radicals produced can interfere with cell regeneration and repair, which over time can lead to accelerated aging and the development of certain diseases. Oxidative stress is defined as an imbalance between increased sources of oxidation and decreased or defective antioxidant mechanisms. This definition lends itself to the notion that a special type of mechanism exists and that deviations from this can affect the homeostasis and potentially cause or worsen disease. Oxidative stress plays an important role in the development of chronic diseases such as cardiovascular disease, diabetes, neurodegenerative diseases and cancer. Long-term exposure to high levels of pro-oxidant factors can lead to structural defects at the mitochondrial DNA level and functional changes in several enzymes and cellular structures leading to aberrations in gene expression. As such, many attempts has been made to restore this “balance” by providing antioxidants to animals and human beings to prevent the ill effects of these free radicles produced by the body tissues. Oxidative stress is a disease driver or an epiphenomenon; which worsen the condition in body and the use of antioxidants treatment may prevent some degree of oxidative stress from occurring, which could play an important role in controlling inflammation and cellular adaptive responses.

Circulating cell-free mitochondrial DNA levels and glucocorticoid sensitivity in a cohort of male veterans with and without combat-related PTSD

Circulating cell-free mitochondrial DNA (ccf-mtDNA) is a biomarker of cellular injury or cellular stress and is a potential novel biomarker of psychological stress and of various brain, somatic, and psychiatric disorders. No studies have yet analyzed ccf-mtDNA levels in post-traumatic stress disorder (PTSD), despite evidence of mitochondrial dysfunction in this condition. In the current study, we compared plasma ccf-mtDNA levels in combat trauma-exposed male veterans with PTSD (n = 111) with those who did not develop PTSD (n = 121) and also investigated the relationship between ccf mt-DNA levels and glucocorticoid sensitivity. In unadjusted analyses, ccf-mtDNA levels did not differ significantly between the PTSD and non-PTSD groups (t = 1.312, p = 0.191, Cohen’s d = 0.172). In a sensitivity analysis excluding participants with diabetes and those using antidepressant medication and controlling for age, the PTSD group had lower ccf-mtDNA levels than did the non-PTSD group (F(1, 179) = 5.971, p = 0.016, partial η2 = 0.033). Across the entire sample, ccf-mtDNA levels were negatively correlated with post-dexamethasone adrenocorticotropic hormone (ACTH) decline (r = −0.171, p = 0.020) and cortisol decline (r = −0.149, p = 0.034) (viz., greater ACTH and cortisol suppression was associated with lower ccf-mtDNA levels) both with and without controlling for age, antidepressant status and diabetes status. Ccf-mtDNA levels were also significantly positively associated with IC50-DEX (the concentration of dexamethasone at which 50% of lysozyme activity is inhibited), a measure of lymphocyte glucocorticoid sensitivity, after controlling for age, antidepressant status, and diabetes status (β = 0.142, p = 0.038), suggesting that increased lymphocyte glucocorticoid sensitivity is associated with lower ccf-mtDNA levels. Although no overall group differences were found in unadjusted analyses, excluding subjects with diabetes and those taking antidepressants, which may affect ccf-mtDNA levels, as well as controlling for age, revealed decreased ccf-mtDNA levels in PTSD. In both adjusted and unadjusted analyses, low ccf-mtDNA levels were associated with relatively increased glucocorticoid sensitivity, often reported in PTSD, suggesting a link between mitochondrial and glucocorticoid-related abnormalities in PTSD.